1. Field of the Invention
The present invention generally relates to a semiconductor device and a method of forming the same, and more particularly, to an optoelectronic device and a method of forming the same.
2. Description of Related Art
An optoelectronic device includes both optical devices and electronic devices, wherein the optical devices include a coupler for receiving an optical signal from an optical fiber and an optical waveguide for receiving and transmitting the optical signal, and the electronic devices include a metal-oxide-semiconductor (MOS) device for controlling the optical waveguide. The MOS device controls the optical waveguide to transform the optical signal into an electronic signal so that the optical signal can be used by other electronic devices.
Conventionally, the electronic devices (for example, the MOS device) are formed on a chip while the optical devices (for example, the coupler and the optical waveguide) are formed on another chip, and the devices are then connected with each other through conductive lines. However, an optoelectronic device fabricated through such a technique takes up too much surface area and has a complicated system. Accordingly, how to form the MOS device, the coupler, and the optical waveguide in a single chip has become highly focused in the industry.
Presently, the technique of forming an optical waveguide on a silicon-on-insulator (SOI) substrate has become very mature. However, if a MOS device is also formed on the SOI substrate, the modeling of the MOS device should be fine tuned again, which is time- and labour-consuming and not economical. Thereby, a method of forming an optical waveguide and a MOS device on a bulk-Si substrate is to be developed.